Freeform Composites: Breaking Free from the Mould.

When making a carbon or glass fibre composite part, a mould is required. The mould supports the flexible composite fabric and adhesive while the adhesive sets. Once the adhesive sets the mould is no longer required. These moulds are expensive to make and wear out over time. As they are expensive, designs tend to change slowly, as the cost of the mould needs to be recovered by repeated use of the mould. But, what if, you only supported a small piece of the part while it cured and then moved on to other parts. Ultimately you could draw the part in 3 dimensional space, just as a pencil draws on flat paper.

The benefit of this would be the ability to create lightweight strong parts. Unencumbered by the restrictions of a mould, with fewer joints and therefore more resilient structures. Is this not already done with 3D printing? In essence yes and no, in 3D printing of composites, either short fibre in resin matrix are used (FDM type) or layers are cut to shape and placed on a flat bed, with successive layers added. Here the joins between the layers are weak and the flat layers are not oriented to give the strongest structures. This new system will produce optimal structures, emphasising the directional properties of carbon and glass fibre to create strong lightweight structures for bespoke engineering applications. These could find uses in new lightweight bridges, car parts, prosthetic limbs, even aircraft wings. The importance of this mould free process, is the fact that it can be easily scaled by building a larger robot. A large robot could therefore build a wing or a canoe whatever the customer required at that time. This new system would create truly flexible composite manufacturing.
Overview of Proposed Research.

The research will create low friction surfaces that will not foul with resin by using fluorinated polymer brushes lubricated by a fluorinated oil. The oil and resin are chemically incompatible and do not wet each other. This surface will be pressed into the composite fabric, deforming it into the required shape, in the same way that Two point incremental forming (TPIF) operatives on aluminium. As the fabric is deformed, the resin will be applied and the composite will be cured. In the first stage of the work by UV, for glass fibre (SMC) and thin carbon fibre panels, in the later stages by microwave curing. To create larger parts, wide carbon fibre tape (1-2cm) will be woven into mats. The ends of the tape will be fed into the system, (with new tape woven into it, as the tapes extend) creating new surface that can be subsequently cured. In this way a continuous weaving, pressing, curing process is created. This would allow for the first time the creation of freeform composite parts. In the early stages this will be limited to panel structures but the long term goal is to integrate this with 3D weaving technology.

Who would benefit from this research?
Composite manufacturers, including those who would still use moulds as the technology for understanding the tool-composite interaction could be used to develop automated adhesive and consolidation systems. Leading to greater automation and more reproducible composite parts.
Robotic and automation industries; due to increased market opportunities.
Schools, Universities and Colleges: The ability to create bespoke parts with minimal waste, would create the opportunity for schools to make composite parts. This would introduce composites to a much younger audience, and help develop their thinking around anisotropic material manufacturing.
Prosthetic limb and medical applications: A scan of a patients limb could be rapidly turned into a bespoke composite socket. Limbs for children could be produce rapidly from lightweight materials. As such the project could have impacts on quality of life, health and well being.
Manufacturing industry: Marine: Marine manufacturing particularly of yachts, tends to be on a relatively small scale. Novel designs such as those of Glider Yachts would become more readily available. Automotive: While most automotive manufacturing would still concentrate on moulds due to the volume, small scale performance vehicles could benefit from this technology, particularly as it would allow for rapid turn-around in the design -testing cycle. Aviation: Longer term this technology will find applications in large scale manufacturing of composite wings and fuselages. Allowing the creation of larger continuous structures, reducing the need for joining technology.
Energy: Wind power: The creation of large structures, such as entire blades in a single process would be facilitated by this system. This would reduce the costs of wind power, both in reduced production time (in particular "finishing time") and in assembly and material costs.

Secondary benefits: Due to the bespoke nature, the proposed research creates opportunities for artists, architects and designers to use composite materials in novel ways. The lightweight, strong and stiff nature of carbon composites is surprising to all the first time it is encountered. The new possibilities for installations based around composites would bring composites to a new audience.

Who would lose out?
Potentially this could be disruptive to mould manufacturers, particularly those specialising in the machining of epoxy block. As this tends to be used in the more niche small volume sectors.